With the rapid development of the road construction and the transportation industry in China, the traffic safety faces a grim situation. The anti-collision guardrail, as a security facility, plays an important role in protecting the traffic safety on roads and bridges.
Generally, the anti-collision guardrail mainly includes three types, i.e., the rigid guardrail, the semi-rigid guardrail and the flexible guardrail. Among them, the rigid guardrail primarily includes the concrete guardrail such as the New Jersey guardrail and the combined guardrail. Such a concrete guardrail has overlarge rigidity, so the abilities of cushioning and absorbing vehicle kinetic energy are weak. When the gravity center of a vehicle is relatively high, the vehicle is prone to turn over the concrete guardrail after it crashed against the concrete guardrail; and when the gravity center of a vehicle is relatively low, the vehicle is prone to turn over laterally after it crashed against the concrete guardrail. The semi-rigid guardrail primarily includes the waveform beam guardrail and the beam-column guardrail. The waveform beam guardrail includes the two-wave guardrail and the three-wave guardrail. Such a waveform beam guardrail absorbs the vehicle kinetic energy by the upward and downward deformations of the steel plate, which results in a large consumption of steel material and poor landscape effects. The beam-column guardrail is constituted of a plurality of parallel steel pipes in the shape of circle or rectangle. The collision grade of these beam-column guardrails is relatively low.
At present, the anti-collision guardrail used on roads and bridges in China is designed and provided for all vehicles, regardless of a big vehicle or a small vehicle. All vehicles crash against such guardrail having the same anti-collision grade when a collision occurs. However, the anti-collision guardrail for protecting small vehicles needs flexible design, and the anti-collision guardrail for protecting big vehicles needs rigid design. The semi-rigid anti-collision guardrail has a relatively low protection grade for big vehicles and has a relatively large consumption of steel material.
In fact, the anti-collision guardrail, as an important safety protection facility, should have a sufficient cushioning capability while stopping a vehicle out of control. That is, the anti-collision guardrail should have not only a sufficient anti-collision grade but also a sufficient cushioning capability, so as to gradually reduce the vehicle kinetic energy. When being crashed by a small vehicle, the anti-collision guardrail should stop or smoothly make the small vehicle drive out at the expected angle by use of the cushioning capability thereof. When being crashed by a big vehicle, the anti-collision guardrail should firstly cushion the big vehicle and then stop or make the big vehicle drive out at the expected angle, so that the big vehicle cannot pass through or turn over the guardrail. In addition, the anti-collision guardrail on roads in a city and roads in a scenic zone should produce a certain aesthetic effect.